Page 217 - 捷運技術 第48期

捷運技術半年刊 第 48 期 213

潛盾隧道受鄰近工區近接施工影響評估及分析

1
௓Ьጳ cЯϛݲ 2

摘要

擁擠的都市地下空間中，於軟弱土層進行潛盾隧道開挖及隧道近接施工之案例日益增
多，而潛盾隧道於掘進期間或完工後，受鄰近工區深開挖影響，可能造成環片側向解壓，進
而促使環片異向變形量增加而導致裂縫形成，嚴重者甚至影響結構穩定性。本文以捷運隧道
近接施工案例，檢討環片結構的安全性，考量環片除現有之受力情況外，應在已有變形條件
下，對後續施工（含捷運主體及鄰近工區）可能產生之解壓、地面加載、地面活載重及地下

水位等因素造成之土水壓力變化，再疊加地震力效應加以評估，並以土壤與結構互制之力學
數值分析模式，利用二維有限元素分析程式 PLAXIS 進行重要性的結構強度及穩定性評估工作。

關鍵字：潛盾隧道、近接施工、變形、垂直變位、土壤結構互制、有限元素模式、數值分析

Evaluations and Analyses of Impact on MRT Shield Tunnels

by Adjacent Construction

1
Bor-Shing Chen cHsu-Chou Yu 2

Abstract

An increasingly common occurrence in confined urban underground spaces is shield tunnel
excavation while other construction is conducted nearby on weak stratums. During excavation or
after completion, deep excavation for adjacent construction could cause tunnel ring to decompress
toward one side leading to an increase in anisotropic deformation of tunnel segments that result in
cracks and even, in serious cases, structural instability.

This paper aims to review the structural safety of tunnel rings by taking construction adjacent
to MRT tunnels as an example. In addition to giving geotechnical considerations to the existing
pressure on the ring, the authors also evaluate soil-water pressure variations for future construction

including MRT main structure and adjacent construction sites that might be caused by the following
factors: decompression, ground loading and surcharge, and underground water level, as well
as seismic effect. Furthermore, based on a numerical approach of soil-structure interaction, the
computer software PLAXIS of 2D finite element analysis has been used significantly to evaluate
structural strength and stability.

Keywords: shield tunneling, adjacent construction, deformed shape, vertical displacement,
soil-structure interaction, finite element model, numerical analysis

1 臺北市政府捷運工程局品保處簡派技正 bschen@trts.dorts.gov.tw
2 臺北市政府捷運工程局南區工程處幫工程司 kidd@trts.dorts.gov.tw